Tattoo Gun versus Tattoo Machine

Secondly, another example; which deserves explanation, of an
interchangeable term is “tattoo machine”. You may be asking
right now, “What is a tattoo machine”? The tattoo machine is
what you probably have referred to as the Tattoo Gun. It is best
not to call it a gun from here on out. What is wrong with calling
it a gun? Well, for starters you may be laughed at by old school
artists. They’ll tell you that nothing actually shoots out of the tattoo
machine, and you don’t have to watch where you point it!
In actuality ink can shoot out of the machine and you kind of
do have to watch where you point it. The real reason for the
use of the term “machine” is that it lets tattoo artists know
when they are talking to another bon a fide tattoo artist.
Almost like a secret handshake, or Cracker-Jack decoder ring.